Hormones on the Rise
by Strike Faster Than Starlight
Summary: Being the winner of another gift game, Izayoi receives a rare perfume as a reward. What he did not expect, was Kuro Usagi's strange behavior after he begun to use it.
1. Chapter 1

**Mondaiji Tachi Ga Isekai Kara Kuru Sou Desu Yo? Belongs to Tatsunoko Taro This is jus for entarteinment**

 **X**

Izayoi glanced at the item in his hand. It was a simple perfume that he gained in a gift game, the host said that it was made from a rare flower that was impossible to find in the human world and extreme difficult to find even in Little Garden,wich left Izayoi curious. He was currently in the room of a Inn that he, Kuro Usagi and Gry were staying.

 _'' I think I'll use some of it and see if Gry and Kuro Usagi like it.''_

Opening the perfume, Izayoi passed a small quantity of it on his neck,forearms and chest. The teen then gave a small sniffle on his shirt.

 _'' What the hell? It doesn't have any type of smell on it! That old bastard! Did he deceive me?''_

Izayoi felt a little annoyed, but decided to give little importance to it.

 _'' Well, it is just a perfume so I shouldn't get all worked up by it.''_

Shrugging his shoulders, Izayoi left the room,passed by the halls and walked down the stairs, making his way to the restaurant. There, he saw a familiar blue head with rabbit ears on it sitting in one of the tables. Smiling, Izayoi approached the person.

-'' Yo, Kuro Usagi.'', Izayoi waved a hand while greeting said girl.

-'' Izayoi-san! I was about to call you for dinner, good thing that you're already here.'', Kuro Usagi spoke with a smile.

-'' Yeah, I was bored, so I thought about joining you and Gry, speaking of him,where he is?''

-'' Oh, Gry-san said that he had a friend in this city and went to see him.''

-'' I see, well what about eating something? I'm starving.''

-'' Yes! I've heard that the food here is heavenly.''

Sitting in the table together, the duo waited till the food was served by one of the waiters. Everything looked icredibly delicious so,without wasting time, they began to eat. After a while, Izayoi noted that something was wrong with Kuro Usagi.

-'' Hey Kuro Usagi, are you alright?'', He tried to ask nonchalantly, but couldn't contain the worried tone on his voice.

She just looked at him in confusion.

-'' Yes I am, why ?''

-'' Well, Your face is all red, so I tought that you were not feeling well.'', The blond pointed out.

-'' It's nothing Izayoi-san, you don't need to worry about it.'', Kuro Usagi said with a grin.

Deciding not to dive into the subject, Izayoi resumed eating. For some time, nothing really happened, but then, Izayoi felt Kuro Usagi comig closer to him and sitting besides him. Trying to ignore this detail, he drank his glass of water, but almost spat it out when he felt a soft hand on his left leg. Looking at the rabbit girl, Izayoi began to feel some nervousness, her face was completely red, she was breathing heavily and her eyes looked dazed. He could swear that the pupils of her eyes took the shape of a heart.

-'' You're so handsome Izayoi-san.'', Kuro Usagi spoke with a dreamy voice.

Cupping Izayoi's cheek with one hand, she moved her face to the crook of his neck and inhaled deeply, making the blond teen shiver.

-'' And you smell so good too...''

-'' K-Kuro Usagi? H-Hey stop it.''

The girl didn't listen to him and moved her hands to his chiseled chest, touching it throgh his shirt. Izayoi almost gasped when Kuro Usagi licked his neck and pressed her well endowed body to his, he held back a groan when the rabbit girl nibbed his neck and gave a strong suck on it. Somehow managing to control his hormones, Izayoi carefully shoved the girl away and stood up.

-'' I-I finished my food so I'll go walk around the city, see you later Kuro Usagi.'',His voice had a hurried tone on it and Izayoi himself felt surprised by this fact. He generally spoke with arrogance or confidence, but there was something terribly wrong with the girl in front of him and the way she was acting shattered his composture, he just felt that he should get away from her for now.

So, without waiting for her reply, Izayoi walked through the restaurant and made his way to the entrance of the Inn. Getting out of it, The blond started with this walk around the city, maybe this could help him to relax a little.

Unbeknowest to him, Kuro Usagi kept her eyes on him till he got out of her sight. Standing up, the girl headed towards the same direction as the blond.

 _'' You're not escaping from me so easily, Izayoi-san.''_

 _xxxxxxxxxxx_

It's been two hours since he left the Inn, and Izayoi could feel as if he was being observed, actually, he had that sensation since the beginning of his ''small tour'' through the city and it honestly was unerving him to a great point.

 _'' Someone is definitely watching me, but who could it be?''_

Looking around, he caught sight of a blue head but it was so fast that it looked like a blur. Still, it was enough to recognize who the person could be.

 _'' It can't be...Kuro Usagi is following me around?''_

Trying to keep his cool, Izayoi calmly walked through the streets before putting power on his legs and began to run with enormous speed, making gusts of wind hit the crowds of people around him. Going through alleys and entering another crowd , Izayoi let out a soft sigh, thinking that the crazy rabbit wouldn't know where he was.

The feeling of something bumping into him brought the teen out of his musings.

-'' I-I'm sorry mister!'', A feminine voice exlaimed.

Glancing down, Izayoi saw a beautiful girl, her hair was crimson and her eyes blue, she also possessed a well endowed figure and seemed to be 16 or 17 years old.

 _'' She is pretty cute.''_

He looked at her with a small smirk.

-'' Don't sweat over it, and I wouldn't mind if a beautiful girl like you would bump into me again.'', At the sight of her blush, his smirk grew.

 _'' Heh, doesn't matter what people say, teasing someone is always fun.''_

His fun was cut short when he felt someone tugging at the sleeve of his shirt.

-'' Izayoi-san.''

That voice made him freeze, it sounded sweet, too sweet to be good. Glancing over his shoulder, Izayoi saw Kuro Usagi standing up behind him with a smile plasted on her face.

-'' Hello, Kuro Usagi.'', He somehow managed to keep his voice calm.

Without saying anything, Kuro Usagi dragged Izayoi with her, leaving the red haired girl with a puzzled look on her face. Going to one of the alleys, she pushed the blond against the wall and stood in front of him with an unpleasant look on her beautiful face.

-'' Who was that girl Izayoi-san?'', She demanded, making the teen gulp.

-'' Nobody Kuro Usagi, she just bumped into me by accident.''

-'' Don't lie to me Izayoi-san! I saw how you flirted with her.'', She practically growled, surprising Izayoi.

-'' Yeah, I thought that she was cute so I just teased her a little, nothing serious you know, and I don't see how this can be important.'', He spoke with desinterest.

Kuro Usagi glared at him and stepped closer to the teen. Izayoi kind of expected her to take her paper fan and hit his head with it, but what he felt wasn't the paper fan, but Kuro Usagi's lips on his.

Izayoi's mind almost went blank when he felt her soft plump lips, he was even more stunned when he felt her tongue search for his and dominate it.

 _'' W-What is happening?''_

Their tongues wrapped around each other in a dance full of lust. Izayoi groaned when Kuro Usagi nibbed his lower lip.

 _'' How can a kiss be so good? This is incredibl- No! Snap out of it Izayoi!_ _''_

Abruptly breaking the kiss, Izayoi pushed Kuro Usagi away from him and began running again.

 _'' Something is really wrong with her, the normal Kuro Usagi would never do something like this.''_

He knew that she would eventually catch up to him, so he should hurry up.

 _'' I need to find Gry, maybe he can help me figure out what is happening.''_

He just hoped that the griffon could be of help to him.

 **X**

 **AN: This will be a two shot, I'm still thinking if I shoud put a lemon scene on it or not, tell me what you think and till the next time! :D**

 **This didn't have a beta so I apologize beforehand for any mistake.**


	2. Chapter 2

Finding Gry was being something rather difficult, that's what Izayoi was thinking at the moment while holding a irritated look on his face. The teen was currently running through the city at tremendous speed, not being able to be seen by the eyes of the citizens. Feminine screams could be heard as skirts and dresses were being lifted up due to the gusts of wind created by the blond. It's been an hour since that kiss with Kuro Usagi. The girl was proving to be quite persistent and she managed to catch up to him a few times during his search, he knew that it wouldn't take long for her to catch him, and _that_ wouldn't be good, at least not in her current state.

 _''I searched on all the stables of this city and still could not find him, this leaves only one more place...''_

Changing directions, Izayoi moved towards the forest that was located at the outskirts of the city. Jumping from tree to tree, the blond man quickly glanced at his surroundings, one reason was to be sure that the crazy rabbit wasn't following him and the other to see if could find some clues about Gry's whereabouts. Thankfully, that did not seem to be a problem because, as he moved further into the forest, he saw a river, and standing at the riverfront, was Gry and another Griffon. To his surprise, Gry leaned closer to the other Griffin and gave what could be considered a kiss on the griffin's ''mouth''.

 _''Didn't knew that this friend of his was actually a female griffon, interesting...But teasing him can wait, I have more important matters on my hands right now.''_

. Increasing the pace, Izayoi put strenght on his legs and jumped, landing right between Gry and the mysterious griffon.

-''Lad?!'', Gry asked with a surprised tone, wich the teen just ignored.

-''I need your help.'' Izayoi told seriously, making the Griffin blink.

-''Can this wait? Right now I'm in the middle of something important.'', He said, nuging towards the female griffon that was besides them, looking at Izayoi with curiosity.

Izayoi shook his head.

-''Sorry but no, it's something serious.'', Gry just sighed.

-''Okay I get it'', Turning to his female companion, Gry spoke,''Could we continue our date in another moment? It looks like my friend here is in a really troublesome situation and needs my help.'', The female Griffin just gave a cheerful smile.

-''Of course we can! Please go ahead and help your friend by all means.'', Gry smiled a little at her response.

-''Thanks Marie, I'll see you later.'', Nodding, Marie opened her wings and flew away in the blue sky. Turning his attention to the blond, he asked,''So, What's the problem Izayoi-dono?''

Izayoi scratched his head while he answered the griffon's question,' It's Kuro Usagi, something strange is happening to her.''

Gry raised an eyebrow.

-''Strange? Like?''

-''Well, it began back in the Inn when we were eating, one moment she was her normal self and in the next one, she was all over me touching my left thigh, putting her hands _inside_ my shirt and even sucking my neck! It weirded mevout, so I got out of the Inn and walked around the city. For a while nothing anormal happened, but then I noticed that she was following me. Gry, she made me go into a alley with her, she pined me against a wall and _kissed_ me! That's not something that the normal Kuro Usagi would do!'', Izayoi exclaimed. The Griffon said nothing for some time, but then decided to make a question.

-''Did you do something different than the usual Izayoi-Dono? Like something that you actually don't do on your normal routine?''

-''Uhm, there was this perfume I used earlier...''

-''Perfume?'' Gry asked warily.

-''Yeah, I acuqired it on a gift game. The host said that it was made from a rare flower.'' Gry had the look of someone that was thinking about many things, then, he glanced at the blond.

-''Come here for a moment Izayoi-dono.'', Izayoi did as requested and stepped closer to the griffon. Gry gave a light sniffle at Izayoi's shirt and his face visibly paled.

-''I was afraid of it, but it looks like I was right.''

-''Right about what?'', Gry's eyes stared directly at Izayoi's purple ones.

-''Izayoi-dono, this perfume that you obtained is made of the flower of lust.'' Gry spoke and this time, it was Izayoi's turn to lift an eyebrow.

-''Flower of lust?''

-''Yes, it's a rare flower that is difficult to find even here in this world of Little Garden, it liberates a pheromone that makes a person get, as you humans like to say, 'extremely horny'.''

-''So that's why that old bastard smiled maliciously at me.'', Izayoi spoke with annoyance,''If it makes the lust within someone increase, then why is not everyone suffering from it too? Why just Kuro Usagi?'', He asked genuinely curious.

-''As you're using it as a perfume, it'll only affect those who already lusted after you or held romantic feelings for you.''

-''What?!'' The blond's eyes widened to their maximum. Gry's words were hinting that Kuro Usagi lusted for him in secret or that she was in love with him, that was something that Izayoi never expected and it definitely caught him by surprise.

 _''So much blackmail and teasing material hehe.''_

Shaking his head to get ride of these thoughts, Izayoi stared at the griffon.

-'' I already get it, but how we'll make Kuro Usagi go back to normal?''

-''Simple...We wait.''

-''Huh?''

-''When the pheromones of the flower are diluated, they get weaker and their effect just works for 24 hours, by tomorrow everything will go back to normal.''

Izayoi sighed.

-''If this is the only way...'', He spoke slowly.

-''Good, now if you excuse me, I'm going to see Marie.'', Opening his wings, Gry gazed at Izayoi,''And one more thing Izayoi-dono...''

-''What is it?''

-''Don't let her catch you no matter what.'', Gry spoke seriously.

-''What would she do to me Gry?'', The mystical beast gave him a solemn look.

-''Have you ever heard about 'reverse rape'?'', At Izayoi's incredulous stare, the Griffin nodded,''Yes, that's the destiny that awaits you if she does catch you, I wish you luck during this trial Izayoi-dono, may the Gods of Little Garden be with you.'', With those final words, the Griffon flew away, leaving a slack jaw Izayoi behind. The blond stood there, completely frozen for 5 minutes, but then, he gave a soft sigh.

-''Looks like I need to be careful, who knows where that rabit could be now.''

-''Right behind you Izayoi-san.'', A voice spoke on his ear. Izayoi's eyes widened, but before he had the chance to do something, he felt a sting on his neck. His vision begun to blur and he fell to the ground. The last thing he saw was Kuro Usagi's smiling face, and then, darkness consumed him...

 _xxxx_

When his eyes finally opened, he was welcomed by the sight of a ceiling. The Sun was already setting and the room was filled with it's orange and red rays. He then felt the cold air hit his body and shivered. Glancing down, Izayoi saw that he was shirtless but thank God his pants were still on him. Looking at his arms, Izayoi saw that his wrists were chained to the bed that he was currently laying.

 _''Heh, as if a mere handcuff would be able to stop me.''_

The teen tried to break the handcuff, but his arms felt too heavy, making him unable to do anything. Hearing the sound of a door opening, Izayoi looked to the bathroom door, and standing there, was Kuro Usagi.

-''So you're finally up Izayoi-san! I'm so happy!'', The rabbit girl spoke merrily. She was dressed in just a white nightgown. It clearly was a little small for her since it clang to her luscious body, and with the Sun rays bathing her, she looked even more beautiful. He gulped and tried to calm his nerves.

-''Kuro Usagi! Why am I chained to the bed? Release me!'', he commanded. Kuro Usagi shook her head while she walked to the bed, getting there, she sat up on Izayoi's waist, her ass dangerously close to his crotch.

-''Nope. I'm sure that Izayoi-san will try to ran away from me if I do it.'', her voice was cheery. She leaned closer and whispered...,''But soon I'll not need to worry about it.'' Her breath was hot, making his ear tingle. Kuro Usagi started to grind her ass against his crotch, earning little moans from the blond. When she grinded harder, Izayoi gasped, and Kuro Usagi took this chance to kiss him deeply. Their tongues moving together in a sloppy kiss that left Izayoi breathless. After a minute,they broke apart, Izayoi's cheeks were red and sweat was beginning to form on his forehead. Kuro Usagi just giggled.

-''I never thought that I would see the arrogant and confident Izayoi-san like this,with a blush on his face and breathing heavily, I love it.'',Taking the nightgown, Kuro Usagi's sexy body appeared in his vision, she was not using a bra, just a purple pantie, her skin was glistening due to the bath that she took before he woke up and her smile was a naugty one. Izayoi tried his best, but the sight was just so erotic that he couldn't control his body, and got a hard on, wich was instantly felt by Kuro Usagi.

-''Is little Izayoi getting happy?'', She sang,''But it most be painful being trapped inside those tight pants! Don't worry, Kuro Usagi will free you.'', Taking the hem of his black pants, the blue haired girl took it off together with Izayoi's underwear and was almost slapped in the chin by the blond's dick when it was finally free from it's confines.

-''Looks like I was wrong on calling you little Izayoi.'' She said with wide eyes, gazing at the 10 inch hard cock in front of her face,''I'll give Izayoi-san a special service.''

 _''Wait, she's not talking about what I think she is right?''_

His answer was the feeling of Kuro Usagi's soft lips and hot tongue on the head of his cock. Izayoi threw his head back, unable to express in a better way how good her lips felt. His pleasure just increased as Kuro Usagi bobbed her head up and down while looking at him right in the eyes. Sometimes, her hand would play with his sac, making the waves of pleasure that were passing through his body almost unbeareble. He then unconsciously began to rock his hips upwards, making the girl take almost own of his big lenght in her throat.

-''K-Kuro U-Usagi, st-stop...If you keep going...I-I'll surely cum.'' Izayoi said between gasps. Seeing his face contourted in pleasure made the girl increase her pace, and in the next moment, white seed flooded her mouth. Slowly taking her mouth from Izayoi's shaft, Kuro Usagi Licked her lips, cleaning them from the cum. This gesture got Izayoi harder again.

-''Oh my, it looks like you didn't had enough Izayoi-san, it seems that I don't have choice.'', Holding her pantie with both hands, she took it out, leaving her as naked as the day she was born.''Now I'm going to use this to make you feel good.'', She stretched her pussy lips, that were completely wet with her love juices. Holding Izayoi's cock, she slowly descended on it. The head touched her plump lips and in the blink of a eye, half of his dick was inside her. Both of them moaned loudly at the sensation. Taking a deep breath, Kuro Usagi kept going down, and even when her hymen broke, she did not stop till she had all of his lenght inside her, although there was still a inch or two to take. Pausing for a moment, Kuro Usagi began to shake her hips, slowy getting used to his impressive shaft. Moving faster, she panted and moaned the blond's name non stop.

-''Haahh...Haahh...Izayoi-san...I love you so much...Izayoi-san!''

-''K-Kuro Usagi, go a little slower!", the girl didn't hear him and moved her hips even faster, the impact between Izayoi's pelvis and her ass caused it to ripple erotically,''This is so good! You're so good Izayoi-san! I'll never let you go!'', She shouted before smashing their lips again. This kept going for a few minutes.

-''Haahh...I'm almost there!'', Kuro Usagi moaned,''Cum with me!'', She exclaimed lustfully.

 _''You know...Fuck that.''_

Izayoi began to thrust harder into her, making the head of his cock continuously hit the entrance of Kuro Usagi's womb.

-''I'm cumming...I'm cumming!'', Both shouted at the same time. Kuro Usagi saw stars at the sensation of the hot semen flowing inside her. When the euphoria of the climax passed, she collapsed on top of Izayoi, smiling with contentment. There was a moment of silence.

-''You got what you wanted Kuro Usagi, can you release me now?'', Izayoi asked with a tired tone.

-''What are you saying my handsome Iza-kun, this is nowhere good enough for me, I need to feel more of you, I _want_ more of you.''

-''...Are you kidding?'', Izayoi asked, completely stunned.

Kuro Usagi grinned.

-''Nope. We're going at it all night.'', She said with a seductive tone.

 _''Seems like it'll be impossible to sleep tonight.''_

 _xxxx_

In the next day, Kuro Usagi was awakened by the small ray of sunlight that passed through the window and hit her face. The girl opened her eyes groggily and turned her head to the left side, only for her eyes to widen.

-''Kyaaahhhh!'', She screamed while jumping out of the bed.

-''Uhm? What's up with being so noisy in the morning?'', Izyoi asked,lazily rubbing his purple eyes.

-''I-Izayoi-san? Why are you here? Why are you naked? Why am _I_ naked?'', Kuro Usagi shouted, her cheeks burning.

-''Huh? Don't you rememer what happened last night?'', He asked.

-''Last night?'', Kuro Usagi furrowed her eyebrows in concentration,then, her eyes widened and her usagimimi moved uncontrollably from side to side,''S-So the both of us did-!''

-''Yeah we did, I was really surprised by the way you acted yesterday, you were so dominant...must be a effect of the perfume.'', He shrugged,'But you know Kuro Usagi.''

-''Y-Yes?''

-''You sure had your fun last night.'', A glint passed through his purple orbs,''But now is my turn, time for round two.'', Before the girl could muster a word, Izayoi pushed her to the bed and soon, moans begun to fill the room.

 _xxxx_

 **AN: So, this is the last chapter, a big thank you to everyone that favorited and followed this story.**

 **Thank you to JudgeDevil, WarRedMachine20, Lust In Your Eyes, Guest and thestarslayer, I appreciate the reviews guys! :D**

 **Hope that this was good enough to all of you!**


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